Add a resetUpdateState() method for clearing update cache, last check timestamp and last checked version.

plugin-update-checker.php

@@ -310,6 +310,16 @@ class PluginUpdateChecker {
 		update_option($this->optionName, $state);
 	}
 
+	/**
+	 * Reset update checker state - i.e. last check time, cached update data and so on.
+	 *
+	 * Call this when your plugin is being uninstalled, or if you want to
+	 * clear the update cache.
+	 */
+	public function resetUpdateState() {
+		delete_option($this->optionName);
+	}
+	
 	/**
 	 * Intercept plugins_api() calls that request information about our plugin and 
 	 * use the configured API endpoint to satisfy them. 
@@ -432,6 +442,7 @@ class PluginUpdateChecker {
 				'<div class="updated"><p>%s</p></div>',
 				apply_filters('puc_manual_check_message-' . $this->slug, $message, $update)
 			);
+			//todo: the update doesn't show up right away, why?
 		}
 	}